This invention relates generally to the field of rotary-motion sanders, polishers, buffers, carpet cleaners, etc., and specifically to the conversion of rotary motion to eccentric rotary motion without altering the number of revolutions per minute (RPM) of the rotary motion and to the collection of dust, water, and similar waste products generated by the aforementioned rotary-motion devices.
Conventional generic orbital sanders, buffers, polishers and carpet cleaners typically drive a sand plate, polishing brush, sand screen pad, carpet brush/sponge at a low speedxe2x80x94typically 175 RPM though sometimes as high as 1000 RPMxe2x80x94in a circular path. This action produces circular scratches on the sanded surface or carpet. Other random orbital sanders or carpet cleaners in existence rely on a high-speed motor to drive an eccentric random action. The action of the high-speed motor is reduced to the desired speed (e.g., 175 RPM) through various mechanical interactions among the gears, shafts, cams, etc. that comprise the sander/cleaner.
Illustrative of the prior art is U.S. Pat. No. 3,857,206 for a compound-motion machine in which an eccentric shaft (19) rotates about a motor shaft (14) to produce an eccentric rotation, and a secondary motion is produced by a secondary rotation about the axis of the eccentric shaft, using interacting gear wheels (31 and 32). (Column 2, lines 45-57) The eccentric shaft is fixed to, and rotates at the same speed as, the drive shaft. (Column 2, lines 16-20) The motor needed to drive this device must be a high speed motor on the order of 4000 to 6000 RPM (column 2, line 33), which establishes an eccentric rotation at the motor speed (4000 to 6000 rpm), while the secondary rotation about the eccentric shaft is reduced in speed by virtue of the gear wheel interaction, to perhaps 300 or 600 rpm depending on the gear ratio and the motor speed. The net motion is rotation at the lower speed, with eccentric motion at the higher speed, requiring and being driven by a high speed motor. There is nothing disclosing or suggesting how this might be achieved with a low-speed motor, nor is there anything suggesting or disclosing how to convert the ordinary circular motion of an existing machine to such a compound motion, without having to simply replace the machine entirely. U.S. Pat. Nos. 4,322,921, 4,467,565 and U.S. Pat. No. 4,845,898 all have similar limitations.
In all of this prior art, an eccentric plate sander is driven by a high-speed (RPM) motor. The eccentric movement is produced directly by the high-speed motor. This high-rotation speed produced by the motor is gear reduced by the gear system into a lower speed rotation. The main drive shaft drives an eccentric drive shaft which in turn drives the gear reduction. This does produce a slow reciprocating action, but requires a high-speed input motor and does not lend itself to adaptation to a low-speed input motor. Nor does it enable a pre-existing low-speed machine to be easily adapted to provide high-speed eccentric action.
Additionally, sanding is typically a very messy job, with dust particles permeating the area being sanded. An inordinate amount of cleanup is required following a sanding job, and it is usually advisable to remove as many movable items as possible from the area to be sanded, prior to sanding, so that these will not become permeated with dust. This introduces much extra work which is preferably avoided. For carpet cleaning, water and other cleaning fluids are applied to the carpet being cleaned, and the rotary motion (or rotary and eccentric motion) is used to create the desired cleansing action. Here, it is often necessary to wait for a day or so for the water and cleaning fluids to dry before using the carpet again, which is inconvenient. Additionally, since much of the dirt being cleaned becomes suspended in the water or cleaning fluid, removal of as much of this water or fluid as possible will simultaneously remove as much dirt as possible. Allowing water or fluid with dirt in suspension to simply dry on the carpet does nothing to remove that dirt and results in a cleaning job of much lesser quality.
It would be desirable to have available a means and method for producing eccentric sanding or cleaning motion using a low-speed (e.g., 125 to 1000 RPM) input motor in which the speed of rotation of the output is precisely the same as the input speed, and in which gear incrementxe2x80x94rather than gear reductionxe2x80x94is used to convert the low-speed input into a higher-speed eccentric movement.
Because many lower-speed input (e.g. 125 to 1000 RPM) sanders and cleaners are already in use in the market, it would further be desirable to provide a modular attachment for such sanders and cleaners which converts this lower-speed input into a higher-speed eccentric movement coupled with a rotation identical in speed to the lower-speed input, with minimum use of space and without major modifications to the original sander or cleaner, thereby avoiding the need to purchase a separate high-speed input sander or cleaner in order to achieve this motion and expanding the range of applications that can be performed by a single piece of sanding or cleaning equipment.
It is further desirable to provide a generic method for converting a lower-speed input of, for example, 175 RPM, into a rotary motion still operating at the example input speed of 175 RPM, but adding eccentric motion at a higher frequency.
It is further desirable for this method to be applied to other rotating sanding devices in existence such as floor sanding edgers, milling machines, and other low speed grinders, as well as hand drill and other rotary motion devices including carpet cleaners.
It is further desirable to provide a means and method for removing as much dust as possible during sanding, so that dust cleanup afterward, as well as the removal of movable items beforehand, can be avoided.
It is further desirable to provide a means and method for removing as much water and cleaning fluid as possible, during carpet cleaning.
This invention uses a low-speed motor input (frequency) to drive a low-speed rotation at the same speed as the motor input, and through gear increment, to drive a much higher-speed eccentric movement. In the prior art, a high-speed motor input is used to drive a similar high-speed eccentric movement, and through gear reduction, a much lower-speed rotation.
First, a fixed gear housing of the device is fixed to a fixed (non-rotating) component of a rotary motion machine, Second, a drive shaft of the device is affixed to that component of the rotary motion machine which generates rotary motion of the given input frequency. Through various combinations of gear interactions and secondary (eccentric) motion driving bars, the device adds a higher-frequency eccentric oscillation to the original rotary motion. The net output is a primary rotational motion at the original input frequency, and a secondary eccentric oscillation of substantially higher frequency.
Waste products such as sand (from sanding) and water/fluids (from carpet cleaning) are collected by attaching a vacuum outlet through the fixed gear housing of the device and through the fixed (non-rotating) component of the rotary motion machine, aid by adding a plurality of suction apertures through the pertinent operating attachment and other pertinent components of the machine. A vacuum skirt is used to enhance the suction from the vacuum outlet and to better contain dust and water.